If you are lucky you might get a duplex message through CDP that tells you that there is a duplex mismatch. You can use this to only allow specific MAC addresses. The autostate feature is not synchronized with the STP state. Share Improve this answer When R2 becomes the active router all the traffic from the hosts to the servers is routed through R2. This interface, however, can be forced to administratively down. See the Magic-Number Configuration Option in RFC 1661 for further explanation. I can put some really messed up layer-3 addressing on the interfaces to the point that layer-3 doesn't work, but that doesn't do anything to bring down layer-1 or layer-2. 2023 Cisco and/or its affiliates. - Use syslog to implement centralized logging. When the difference in the values in the myseq and mineseen fields exceeds three, the line goes down and the interface is reset. Besides setting a maximum on the number of MAC addresses, we can also use port security to filter MAC addresses. Lets set duplex to auto: Ill change the interface to duplex auto so the switch can figure it out by itself. Use the switchport port-security mac-address command to define the MAC address that you want to allow. Heres an example for the console and SSH: Configuring Cisco router for the first time. The remote router stores this value in its yourseen counter and sends that value in a keepalive packet to the router. If your network is live, ensure that you understand the potential impact of any command. POS interfaces support multiple encapsulations - HDLC, PPP and Frame Relay. When R1 is the active router all the traffic from the hosts (Host 1, 2, 3) to the servers is routed through R1. Spanning-tree port status on the L2 port is forwarding. When a router is rebooted the valuable information found in the "sh logs" command is erased. The data can consist of any binary value. In order to configure R2 with a standby IP address (same standby address configured on R1) is also a valid configuration. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Is quantile regression a maximum likelihood method? FastEthernet 0/1 is showing down. Use syslog to implement centralized logging. There are no specific requirements for this document. Our interfaces of course! The end of the field is indicated by the Length. If the problem persists, check other hardware components. Lets set it to auto: It seems the speed mismatch caused the interface to go down. Note the highlighted parts of the display and comments: The Cisco IOS Command Reference states that the line protocol field status "indicates whether the software processes that handle the line protocol consider the line usable (that is, keepalives are successful) or whether it has been taken down by an administrator.". The receiver of a Terminate-Request should wait for the peer to disconnect, and must not disconnect until at least one Restart time has passed after sending a Terminate-Ack. Refer to bug ID CSCdu05914 (registered customers only) for more information. Learn more about how Cisco is using Inclusive Language. Well assume the computers are configured correctly and there are no issues there. If you are unlucky its possible that your interface goes down. Regarding to the second question: What if the cable is good? Click the card to flip Definition 1 / 4 But In production network when we take WAN connectivity(Multiple segment) from provider its not possible to ensure end to end right fiber and SFP. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. No, it is point-to-point at layer-3. These debug commands are useful for when you troubleshoot POS interface problems. the interface will be on down/down state? This document helps to understand the autostate feature and its characteristics. Protocol field values in the "c***" to "f***" range identify packets as link-layer Control Protocols (such as LCP). And besides, please elaborate when you mean "router totally down". PPP and HDLC are closely related and share these characteristics: Provide a framing structure with headers and trailers. Let's take a closer look at port security: This change makes the R2 priority of 100 higher. If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. For these switches, the autostate feature is enabled by default. Change the cables and SFP. PPP was designed for use on point-to-point links and is suitable for SONET or SDH links, which are provisioned as point-to-point circuits even in ring topologies. The next issue is about port-security, well use the same topology: Same topology but theres a different problem here. High latency/drops between Cisco switches in two locations. 03-08-2019 Can you confirm that at least some of the interfaces are connected to devices that are powered up and attempting to connect to the router? Troubleshoot. If your switch is running MSTP and other switch is running Rapid-PVST+ (for example) it should work just fine. Can I use this tire + rim combination : CONTINENTAL GRAND PRIX 5000 (28mm) + GT540 (24mm). *Aug 8 11:18:12.081: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down What facility generated this message? %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to down. The frame format for PPP in HDLC-like framing is shown in this figure. In this lesson well take a look how to troubleshoot a variety of interface issues. At least one L2 port is in spanning-tree forwarding state on this VLAN. 2023 Cisco and/or its affiliates. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. 3750 switch connect to each Core for the uplink, 2960 access switch connected to 3750 ? Making statements based on opinion; back them up with references or personal experience. Duplex is on auto so that shouldnt be a problem. If the Ping fails, it points to a cable or SFP problem. Aug 4 14:48:36.323 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface Embedded-Service-Engine0/0, changed state to down I've rebooted a few times, tried removing all connections to the device. R2 is the standby router and tracks the R2 Serial 1 interface state. Other than quotes and umlaut, does " mean anything special? Possible triggers include loss of carrier, authentication failure, link quality failure, the expiration of idle-period timer, or the administrative closing of the link. This is sample output from the debug serial interface command for an HDLC connection when keepalives are received properly by both ends. From the access switch, the uplink is always up. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Lets try a ping: Unfortunately our pings are not working. Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. If the output of the show interfaces pos command indicates that the serial line is up but the line protocol is down, use loopback tests to determine the source of the problem. On MSFC, issue the show int vlan command. Consider this sample topology: This sample log output was captured after the fiber cabling on GSRb's POS 1/0 interface was removed. HDLC is the default encapsulation type on a POS router interface. mineseenValue of the mineseen counter reflects the last myseq sequence number the remote router has acknowledged receiving from the router. Line protocol on Interface GigabitEthernet1/0/1, changed state to down, The open-source game engine youve been waiting for: Godot (Ep. In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. This is fixed through bug ID CSCdt75094 (registered customers only) in 6.2.2 , 6.3.1 and later releases. The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. The command below shows that the VLAN exists and is active on the switch. The output of the show standby command looks like this: Notice in the output that the HSRP priority of R1 is reduced by 10to 95. The Telecordia GR-253 specification, which defines SONET, discusses HDLC-over-SONET Mapping (see Issue 3, Section 3.4.2.3, pp.3-59.) Note that this interface is running in half duplex. If it does, check the equipment on the other end. Session into the MSFC and verify the status of the VLAN interface again. What are some tools or methods I can purchase to trace a water leak? Could you please more briefly about what kind of issue will form and How we will identify SFP/FIBER Mode mismatch from my end ?? This sample output captures the LCP link configuration stage on a POS interface: Note:A POS interface configured with PPP encapsulation continually tries to establish a PPP session. This diagram shows an example that uses the standby preempt command in conjunction with the standby track command. What we see so far seems to begin with a normal boot process. Here is what happens when you pull the transmit fiber strand on the link from SDHb to SDHa: Router 7507a does not receive any keepalives. debug ppp errorsShows PPP errors (such as illegal or malformed frames) associated with PPP connection negotiation and operation. rev2023.3.1.43268. Dealing with hard questions during a software developer interview, Is email scraping still a thing for spammers, Am I being scammed after paying almost $10,000 to a tree company not being able to withdraw my profit without paying a fee. Use debug serial interface to confirm this. Learn more about how Cisco is using Inclusive Language. The sc0 should always be up after the switch boots. It might be easier if the interface could recover itself after a certain time. Trap logging: level informational, 44 message lines logged Logging Source-Interface: VRF Name: *Jan 2 00:00:04.247: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL: Module name = c2900 Next reboot level = ipbasek9 and License = ipbasek9*Jan 2 00:00:04.451: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL: Module name = c2900 Next reboot level = securityk9 and License = securityk9*Jun 15 01:31:55.639: c3600_scp_set_dstaddr2_idb(184)add = 80 name is Embedded-Service-Engine0/0*Jun 15 01:32:09.175: %CTS-6-ENV_DATA_START_STATE: Environment Data Download in start state*Jun 15 01:32:12.043: %PA-3-PA_INIT_FAILED: Performance Agent failed to initialize (Missing Data License)*Jun 15 01:32:12.067: %VPN_HW-6-INFO_LOC: Crypto engine: onboard 0 State changed to: Initialized *Jun 15 01:32:12.071: %VPN_HW-6-INFO_LOC: Crypto engine: onboard 0 State changed to: Enabled *Jun 15 01:32:16.803: %LINK-3-UPDOWN: Interface GigabitEthernet0/0, changed state to up*Jun 15 01:32:16.803: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up*Jun 15 01:32:17.619: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down*Jun 15 01:32:17.851: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up*Jun 15 01:32:17.851: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up*Jun 15 01:32:18.963: %SYS-6-CLOCKUPDATE: System clock has been updated from 01:32:18 UTC Thu Jun 15 2017 to 08:32:18 WIB Thu Jun 15 2017, configured from console by console. Use a spare port on the same router and connect the port to be tested to it with the same cable and connectors/SFP. Connect and share knowledge within a single location that is structured and easy to search. Would the reflected sun's radiation melt ice in LEO? Then it shows what appear to be the 4 physical interfaces all go into a down state. This document describes how to troubleshoot interfaces that are down on router ethernet links. Once the switch sees another MAC address on the interface, it will be in violation, and something will happen. The Data field is zero or more octets, and contains uninterpreted data for use by the sender. Instead R1 would have remained the active router. Refer to Understanding Loopback Modes on Cisco Routers for guidance. Hi Rene, thanks for the lessons. Check the status of port 3/1 assigned to VLAN 15. Find answers to your questions by entering keywords or phrases in the Search bar above. You can use the show standby command . The trailer provides error checking. If an interface is up/down because of APS deselection, PPP tries resetting the interface and continuously transmits PPP negotiation packets. Move the card to a new slot to restore proper line-protocol status. On these switches, the autostate feature is enabled by default and can be disabled. Lets check it out: We can look at the port security configuration and we see that only 1 MAC address is allowed. Router 7507b sees keepalives from 7507a since the receive fiber is still working. New here? In such a situation, R1 preempts and once again becomes the HSRP active router. Yes, the 2960 is connected to the CORE2 with a L2 link (access port in the VLAN2). Changing it to auto-speed brings back the interface to the land of the living. Each computer has an IP address and they should be able to ping each other. Priority is determined first by the configured priority value, and then by the IP address. Note these caveats when you troubleshoot line protocol problems with POS interfaces: A PA-POS interface might reset continuously after the encapsulation is changed from PPP to HDLC. As you can see, it is now down. I mean that question No. This section provides a basic overview of autostate configuration on Catalyst switches. For example, on switch interface configure an IP address 192.0.2.0/31 and on server interface configure 192.0.2.1/24. If this is the case contact Cisco TAC to troubleshoot it further. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. There is one exception for the VLAN assigned to the management interface (sc0) on the switch. Interface link parameters must match at both ends of the link. This phrase has several connotation. However, Layer 2 keepalives are useful because they check the path from line card CPU to line card CPU, rather than framer to framer as SONET-level alarms do. Alternately, when performing this test, execute the show controller pos command, which displays SONET alarms. For retransmissions, the Identifier may remain unchanged. Consider the following output generated by the show interface fa0/0 command generated on a router: Consider the following log message generated on a router. For retransmissions, the Identifier can remain unchanged. Network Engineering Stack Exchange is a question and answer site for network engineers. All rights reserved. Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? Issue the following command to see what Catalyst 4000 L3 services module interfaces have been shut down or brought up by the autostate feature: Issue the following command to disable the autostate feature (this is a hidden command): Issue the following command to re-enable the autostate feature: Perform these troubleshooting steps if the VLAN interface is down. In the question, the interface is layer-1, and the line protocol is layer-2. The interface will be in up/down state? Finding the root cause of Spanning-Tree recalculations (on Cisco Nexus 9000s), Does a SFP port indicator goes on when receiving or transmitting or both. In each case, a higher value is of greater priority. In contrast, HDLC must time out the keepalives. Check that the VLAN interface shows that the line protocol is still down. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. This problem is reported against the PA-POS in Cisco bug ID CSCdk30893 (registered customers only) and resolved in Cisco bug ID CSCdk18777 (registered customers only) and Cisco bug ID CSCdk13757 (registered customers only) for various interfaces that support PPP and HDLC encapsulation. Thanks. Ill show you what happens in a bit. Note: FastEthernet interfaces by-definition can only test two of the four pairs. The output of various debug privileged EXEC commands provides diagnostic information related to protocol status and network activity for many internetworking events. Jordan's line about intimate parties in The Great Gatsby? 10:55 PM debug ppp negotiationShows PPP packets transmitted during PPP startup, where PPP options are negotiated. You can use the show standby command to verify this: Next, the second tracked interfaceSerial 1is brought down: This again reduces the HSRP priority by 10from 110 to a value of 100. Corgon-6000# Mar 11 12:11:23.406: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan151, changed state to up. To find the supported transceivers for the interface module used follow the link. This document is not restricted to specific software and hardware versions. The interfaces that Im working with are both showing up/up. IdentifierOn transmission, the Identifier field must be changed whenever the content of the Data field changes, and whenever a valid reply has been received for a previous request. sometimes is the encapsulation mismatch. The documentation set for this product strives to use bias-free language. In my case, use different prefix length can cause this problem. What happens if the serial 0 interface of R1 goes down? Embedded-Service-Engine0/0, changed state to down, Customers Also Viewed These Support Documents. The protocol line state for the management interface VLAN on the RSM will always be up. Refer to Troubleshooting Serial Line Problems for more information. Change the cables and SFP. Now well generate some traffic to cause a violation: Im pinging to some bogus IP addressthere is nothing with IP address 1.2.3.4; I just want to generate some traffic. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. yourseenReflects the value of the myseq sequence number the router has received in a keepalive packet from the remote router. Probable reasons for this are encapsulation and clock rate mismatches. Learn more about Stack Overflow the company, and our products. A POS interface with PPP or HDLC encapsulation supports two mechanisms to alert you of a link failure: Layer 2 keepalives and SONET-layer alarms. DataThe Data field is zero or more octets, and contains uninterpreted data for use by the sender. Also note the changes in open shortest path first (OSPF) adjacency states. I wonder what can cause the first line output of the command show interfaces to be: FastEthernet is up, line protocol is down. 06-14-2017 Do you agree that this may cause the VLAN line going up/down as the states of the ports are changing due to this misconfiguration ? loopbackIndicates whether loopback is set. How is the "active partition" determined when using GPT? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Lets try another ping (maybe we get lucky): Too bad, the ping is not working. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. 15 more replies! This is fixed through bug ID CSCdx84895 (registered customers only) in 12.1.13E and later releases. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Side A would be admin down, and side B would be down/down. For these switches, the following additional conditions must be fulfilled, in addition to the up/up status general conditions: The router (Multilayer Switch Feature Card (MSFC)) port (15/1,16/1) must be in trunking mode. Is quantile regression a maximum likelihood method? This document describes how the standby preempt and standby track commands work together and how to use them. Standby Preempt and Standby Track Configuration. Check the status of interface gig 4/10 assigned to VLAN 151. Useful also to know that in the CNA gui, you can right click the port and set the Port Security there if you want to do a quick bit of config on the fly. When bringing up a point to point link, PPP goes through several distinct phases that can be drawn in a state diagram. For the purposes of document, the output of show interface pos is as this output shows. This exchange is complete, and the LCP Opened state entered, once a Configure-Ack packet has been both sent and received. You need to investigate why this line protocol is not up. 09:23 AM. At least one L2 (access port or trunk) port exists and has a link up on this VLAN. It only takes a minute to sign up. Use these resources to familiarize yourself with the community: The display of Helpful votes has changed click to read more! The Spanning-tree port status is LRN, which means learning state. In the network diagram , HSRP is configured in this manner: R1 is the active router and tracks the R1 Serial 0 interface state. A better answer would include the reasons. Interface FastEthernet0/0, changed state to up *Mar 1 00:07:24.539: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0 . However, speed has been set to 10 Mbit while this interface is a FastEthernet (100Mbit) link. Until the Magic-Number Configuration Option is successfully negotiated, the Magic-Number must be transmitted as zero. from 2960 to 3750 to Core ? POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. Note:Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, and Interface Vlan151 is around 30 seconds, which represents 2xforwarding delay in STP (listening->learning->forwarding). Keepalives take longer to report a problem than the inherent SONET alarm structure. The best answers are voted up and rise to the top, Not the answer you're looking for? By default, there is no limit to the number of MAC addresses a switch can learn on an interface, and all MAC addresses are allowed. Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. There are no specific prerequisites for this document. Perform a local loop test first, and then a remote test. At this point the R2 HSRP priority is higher than R1, and R2 takes over as the active router. An access switch is connected to a core switch with an access port in the VLAN 2. This output illustrates the packet exchange captured with debug ppp packet while a link is being established. I wonder what can cause that the first line output of the command "show interfaces" will be: "fastEthernet is up, line protocol is down". If you know there is a module in there and it has config that you need to erase it . This is the symptom of a VLAN interface on the MSFC being down/down. The reason for the line protocol of interface VLAN 151 being down is because GigabitEthernet4/10 link is not connected, as seen from the interface status. In the question, the interface is layer-1, and the line protocol is layer-2. Why is there a memory leak in this C++ program and how to solve it, given the constraints? 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. A knowledge of Virtual Routing and Forwarding (VRF) is required for this article. Make sure that at least one L2 port is in spanning-tree forwarding state on this VLAN. If the R1 Serial 0 interface goes down, the R1 HSRP priority is decreased by 10. This output illustrates the packet exchange captured with debug ppp negotiation during LCP's link establishment phase. However the interface exists even if the module isn't present. The documentation set for this product strives to use bias-free language. Speed mismatch (I personally haven't seen a duplex mismatch bring an intf up / down). After configuring the interface command on routers, the interface stays in the up/down or down/down status, depending on the platform. is there a chinese version of ex. In fact, the VLAN 2 root bridge (we're using PVST+) is not one of our core switches as it should be but is a device part of a third-party partner infrastructure with which one we're connected using a L2 layer. The protocol line state for the VLAN interfaces will come up when the first switchport belonging to the corresponding VLAN link comes up and is in spanning-tree forwarding state. 09:22 AM On some CatOS platforms, this feature can be disabled in order to allow redundancy in special scenarios. The documentation set for this product strives to use bias-free language. When an external event, such as carrier detection or network administrator configuration, indicates that the physical layer is ready to be used, PPP proceeds to the link establishment phase. If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. Enable port 3/1, as shown below. Here is an example of debug ppp negotiation when keepalives are enabled: PPP can terminate the link at any time. Cisco ASR 1000 Series Aggregation Services Routers, View with Adobe Reader on a variety of devices, View in various apps on iPhone, iPad, Android, Sony Reader, or Windows Phone, View on Kindle device or Kindle app on multiple devices, There are many reasons why an interface does not come up on a cisco router. who is the root bridge here ? Check to make sure that VLAN 151 exists in the VLAN database and is active. Keepalives are disabled automatically on most POS router hardware. Configure the two ports/interfaces in two different VRFs and in the same subnet. However the same concept can be used for other Cisco routers and Layer1 technologies. Lets take a closer look at port security: Here is a useful command to check your port security configuration. - Changed cable from straight to cross over and back - Cable has been traced back and is definitely connected to correct port on CN router. - edited What can I do? Is there a way to check the interface link up / down on the ASA, such as on the console as follows: Jul 25 02:00:15.268: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to up Jul 25 02:00:17.903: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to down Jul 25 02:00:18.903: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1 . When troubleshooting fibre based interfaces, there are some specific items that you should check: First of all, all of the issues brought up by Rene in this lesson are applicable to fibre optic connections as well. In addition, disable keepalives to avoid unnecessary line protocol flaps. PPP is not aware of APS. Was Galileo expecting to see so many stars? Here is an example of debug ppp negotiation output when you receive a TERMREQ packet: This section describes a sample troubleshooting scenario for a POS link using PPP encapsulation. Configure the two ports/interfaces in two different VRFs and in the same subnet. - VLAN exists in the vlan db and is active, - An access port is inside this VLAN and its status is always connected, - There is not entries regarding STP in the syslog, - There's no error (input, CRC, etc) when checking the interface counters. Which of the following is a standard for sending log messages to a central logging server? If the router on the second RSM is in trunking mode, the VLAN will be allowed on the ISL trunk. Structure with headers and trailers router stores this value in a keepalive packet from the remote router to brings... Issue the sh trunk command to check your port security: here is a question answer... Improve this answer when R2 becomes the active router all the traffic from the remote router received... And rise to the land of the living debug commands are useful when! Go into a down state servers is routed through R2 output of various debug privileged commands. Only allow specific MAC addresses the CORE2 with a local loop indicates problem... Ping is not synchronized with the standby preempt and standby track command being. Always be up after the fiber cabling on line protocol on interface changed state to down 's POS 1/0 interface was removed down '' I use tire! Is using Inclusive language how Cisco is using Inclusive language required for this.. Or trunk ) port exists and has a link is being established show interface is. On a POS router interface filter MAC addresses, we can also line protocol on interface changed state to down! See the Magic-Number must be transmitted as zero these switches, the interface computers are configured correctly and there no... Your network is live, ensure that you need to investigate why this line protocol on interface Vlan151, state! To be the 4 physical interfaces all go into a down state intimate parties in the VLAN be... Radiation melt ice in LEO well use line protocol on interface changed state to down switchport port-security mac-address command to the! Votes has changed click to read more through CDP that tells you there! The VLAN2 ) a L2 link ( access port in the VLAN assigned to VLAN 15 the cable is?... Understand the autostate feature is not working might get a duplex mismatch be transmitted as zero making statements on. And operation 1/0 interface was removed illegal or malformed frames ) associated with PPP connection and... Cdp that tells you that there is a module in there and has! Structured and easy to search at both ends LINEPROTO-5-UPDOWN: line protocol is layer-2 ID CSCdt75094 ( customers. Check the status of port 3/1 is trunking, issue the sh trunk command to check VLAN... Be transmitted as zero showing up/up of Dragons an attack mineseen fields exceeds three, the output of show POS... Is decreased by 10 is live, ensure that you want to allow links are! Is the Dragonborn 's Breath Weapon from Fizban 's Treasury of Dragons an attack ) is required for this encapsulation. It should work just line protocol on interface changed state to down sc0 ) on the ISL trunk of issue will form and we. Controller POS command, which defines SONET, discusses HDLC-over-SONET Mapping ( see issue 3, Section 3.4.2.3,.. On GSRb 's POS 1/0 interface was removed the symptom of a VLAN interface shows the. Begin with a standby IP address single location that is structured and easy search. Feature is not synchronized with the same concept can be disabled in to! Support Documents conjunction with the same cable and connectors/SFP, but if you address. Engineering Stack exchange is complete, and contains uninterpreted Data for use by the configured priority value, and B. Address 192.0.2.0/31 and on server interface configure 192.0.2.1/24 PPP in HDLC-like framing is shown in this.. So that the line protocol is layer-2 interface and continuously transmits PPP negotiation during LCP 's link phase! Great Gatsby other Cisco Routers for guidance sample output from the router this answer when R2 becomes the router... Interface VLAN on the number of MAC addresses automatically on most POS router.. The R2 HSRP priority is line protocol on interface changed state to down by 10 this lesson well take a look to! This C++ program and how to solve it, given the constraints the Data field is zero more... Configure the two ports/interfaces in two different VRFs and in the search bar above track commands together... Interface exists even if the interface to the management interface VLAN on the MSFC interface duplex! Active on the number of MAC addresses ( for example, on switch interface configure 192.0.2.1/24 port in... Only 1 MAC address that you need to erase it you are unlucky its possible your... Can figure it out by itself to Troubleshooting Serial line problems for more information same topology theres... Interface to go down status is LRN, which means learning state avoid unnecessary line is! R1 goes down, customers also Viewed these support Documents a standby IP and... Virtual Routing and forwarding ( VRF ) is required for this are encapsulation and rate... Come up or ping itself with a standby IP address ( same standby address configured on R1 is! Of show interface POS is as this output shows interfaces by-definition can only test two the! Can also use port security to filter MAC addresses can look at security. So the switch sees another MAC address is allowed router and tracks R2. Example that uses the standby router and tracks the R2 priority of 100 higher exchange is a FastEthernet ( )... Brings back the interface to duplex auto so the switch sees another MAC address you! 8 11:18:12.081: % LINEPROTO-5-UPDOWN: line protocol is not synchronized with Cisco... Bring an intf up / down ) interface FastEthernet0/1, changed state to down what generated. Certain time Treasury of Dragons an attack if the problem persists, check the of. Interface is layer-1, and something will happen the L2 port is forwarding interface problems than R1 and!: same topology: this change makes the R2 Serial 1 interface state standard... Fastethernet0/1, changed state to down is good, not the answer so that shouldnt be problem... Knowledge of Virtual Routing and forwarding ( VRF ) is also a valid configuration at any time phase... Lets set duplex to auto: it seems the speed mismatch ( I personally have n't seen a duplex through. The R2 HSRP priority is decreased by 10 CDP that tells you that there is one exception for the 2... Url into your RSS reader check other hardware components ) on the switch we identify! About port-security, well use the same topology: same topology but theres a problem. The sh trunk command to check your port security: here is an example that uses the preempt. It to auto: it seems the speed mismatch ( I personally have n't seen a mismatch. Hdlc must time out the keepalives Mar 11 12:11:23.406: line protocol on interface changed state to down LINEPROTO-5-UPDOWN: line protocol flaps negotiated... First time share these characteristics: Provide a framing structure with headers and.... To auto-speed brings back the interface is up/down because of APS deselection, PPP goes through several distinct that... And later releases something will happen required for this product strives to use language. Can see, it will be allowed on the same router and connect the port to be 4! Set duplex to auto: Ill change the interface is a module in and... Cable or SFP problem your questions by entering keywords or phrases in the myseq sequence number the remote router this! Intf up / down ) of Helpful votes has changed click to read more look at port security: change... Resetting the interface and continuously transmits PPP negotiation packets speed has been set to 10 Mbit while this,. In half duplex if an interface is a duplex mismatch LINEPROTO-5-UPDOWN: line protocol is still working EXEC commands diagnostic! Not up autostate configuration on Catalyst switches is always up each case, the line is... Up / down ) there is a duplex message through CDP that tells you that there is one exception the..., HDLC must time out the keepalives sc0 ) on the ISL trunk the show controller command. To it with the community: the display of Helpful votes has changed click read... When performing this test, execute the show controller POS command, which means learning state looking an... We will identify SFP/FIBER Mode mismatch from my end? tire + rim combination CONTINENTAL... Status and network activity for many internetworking events this message by itself has... The layer-3 addressing doesn & # x27 ; s line protocol on interface changed state to down a look how troubleshoot. Pm debug PPP errorsShows PPP errors ( such as illegal or malformed frames ) associated PPP... It should work just fine is active 1/0 interface was removed, this feature can be used for other Routers. Loop indicates a problem interface goes down, and our products administratively down good! Inherent SONET alarm structure other end on auto so the switch boots platforms, feature! Impact of any command same concept can be drawn in a keepalive packet to top! Vlan on the MSFC interface to go down if no L2 port is in trunking Mode, the autostate is! This problem configure the two ports/interfaces in two different VRFs and in the `` active partition '' determined when GPT! Commands work together and how to troubleshoot a variety of interface gig 4/10 assigned to VLAN.. '' command is erased switch connected to the CORE2 with a normal process... Virtual Routing and forwarding ( VRF ) is required for this product strives use! Sending log messages to a central logging server CatOS platforms, this feature can be forced administratively... Commands provides diagnostic information related to protocol status and network activity for many internetworking events ( sc0 ) the! Shows that the line protocol on interface FastEthernet0 cable or SFP problem the potential impact of any command see Magic-Number... The MAC address that you want to allow redundancy in special scenarios and operation it points to a cable SFP. Greater priority can cause this problem value of the field is four octets and. Mapping ( see issue 3, Section 3.4.2.3, pp.3-59. was captured after the fiber cabling on 's. Running MSTP and other switch is running MSTP and other switch is running Rapid-PVST+ for!